linux-wandboard

[media] DocBook: partial rewrite of "Opening and Closing Devices"

This section was horribly out of date. A lot of references to old and
obsolete behavior have been dropped.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>